How to Storm a Castle

It's castle-storming season on Game of Thrones. Daenerys Targaryen's elite Unsullied troops managed to sneak in and conquer Casterly Rock without having to climb its walls on horrible ladders. The Lannister army they'd intended to attack actually marched south and laid siege to Highgarden, though the battle happens off-screen. And while Daenerys of the very long name managed to catch the Lannister loot train out in an open field and slaughter them, she would need to mount a much-discussed attack on King's Landing and its Red Keep to remove Queen Cersei from power.

There's perhaps no military action older than castle storming. Whether you're talking about paleolithic Scotland, medieval France, or the fictional kingdoms of Westeros, the pattern appears to be the same: As soon as people had any possessions at all, other people have coveted the lands and possessions of their neighbors. And so, the people with lands and possessions built castles for protection. Siege warfare against those castles is brutal and blunt. It's a style of fighting characterized by a combination of ungodly long, boring waits punctuated by short spurts of terrifying action.

There is a lot more to besieging a walled fortress than simply running around with ladders. A lot more.

Castle Basics

It takes more than a forbidding appearance for a castle to keep attackers at bay. The first castles were merely earthen heaps surrounded by a wooden palisade wall. But they quickly got much better. Over time, a body of castle-building knowledge arose and all good castles more or less followed the same rules.

For example, a well-designed castle is never square. The corners on a square castle are vulnerable to attack because the ninety degree angle makes it difficult to mass defenders at those points, so any good field general would concentrate his attacking forces there. To counter this, castle designers erected protruding towers at intervals, giving defenders a redoubt where they could shoot downward with a wide field of view.

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In addition, those towers were built as tall as possible. When hurling machines like catapults and trebuchets are forced to shoot in high arcing trajectories, they lose much of their effectiveness. Plus, when defenders drop rocks from high elevations, they have a lot more smashing power.

Typically there was an elevated walkway just behind the top of the castle walls called a rampart. There were openings in the upper walls, accessible to the men on the ramparts, called embrasures, through which archers could shoot.

The main way into a castle, of course, was through the gate. Gates were always exceedingly well protected. Typically, large strong towers flanked both sides of the gates, and the towers were always manned with defenders. The entrance to a castle was often a steel grate called a portcullis, a walkway, and then another portcullis. Above the walkway were the "murder holes," openings through which rocks and spears could be thrust down on attackers trapped between the portcullis grates.

Casterly Rock

HBO

Casterly Rock, with its multiple towers and textbook perfect lines-of-fire, appears to be a good example how to design a castle. Dragonstone, on the other hand, is something of an architectural nightmare. Its multitude of thin projecting walls provide unintended cover for attackers below, and its utter lack of towers and bastions are inexcusable.

Pitched Battles vs. Sieges

Prior to the age of modern, mechanized warfare, there were but two major kinds of military action: the pitched battle and the siege. A pitched battle was just what it sounds like, with soldiers, mostly on foot, advancing on the enemy as quickly as possible. Frontal assaults, flanking maneuvers, and ambushes—these were the simple tactics employed in pitched battles from the Battle of Marathon in 490 BC continuing through the time of the Roman Empire, into the Middle Ages, and beyond.

We've seen this kind of thing in the show numerous times already. Daenerys' horde of Dothraki ambushed the Lannister loot train and routed them in the previous episode. In season 6's "Battle of the Bastards," Ramsay Bolton's army manages to flank and then encircle Jon Snow, at least until reinforcements come.

HBO

The other type of military action is a siege, and ever since season 1, Game of Thrones characters have been worried about them (King Robert Baratheon wisely explains the foolishness of meeting the Dothraki in a pitched battle as opposed to hiding behind the castle walls.) When one side had a big advantage over the other side in terms of manpower or equipment, the other side could choose not to meet the enemy on the field of battle, but instead retreat to a walled city or fortress. Here, within thick protective fortress walls made of limestone or sandstone or flint, the defenders could hole up for months. Depending on the supply of food and water within, those inside could often outlast the enemy encamped beyond the walls.

It was incredibly hard to capture a castle, but plenty have tried both in fiction and in real history. The attackers could try to outwait the defenders and force them to surrender by starving them out. They could use some kind of subterfuge against the enemy. Or they could lay siege.

Early Tactics

Modern-day Stirling Castle

Getty Images

So, what were the tools and tactics that commanders could use to lay siege and conquer a castle? There were several well-known techniques, but none of which were guaranteed to be successful or easy to use. One method was the blockade, whch involved simply surrounding the castle with troops and ships to prevent any food or supplies from getting in. A blockade sometimes worked, but often the garrison (the group of soldiers within a fortress or castle) was usually better supplied than the attacking army and could outlast the besiegers, at least until a relieving army could fight its way in.

Another technique was to talk their way through the castle walls. Messengers would try negotiation and compromise, but threats, coercion, and bribery often worked better. The concepts of loyalty and national identity were somewhat more fluid in ancient and medieval times than they are now. A commander sometimes could be persuaded to change sides—or maybe to at least sit this one out if the attackers made their threats fearful enough or bribes big enough.

For example, during a 12th century siege of a castle in Crema, Italy, the attacking army took captured soldiers, cut off their heads and then tossed their heads like footballs in full view of the besieged castle. It didn't work this time. The defenders within the castle went mad with rage and took their prisoners and ripped them limb from limb on the castle ramparts.

Conversely, the castellan (the commander of the castle and the king's loyal man) might capitulate if certain promises of safety, payment, and bounty were provided. It was the rare castellan who was truly loyal and couldn't be bribed, but in those cases, an attacker's fallback strategies might include using spies or inciting a mutiny among the rest of the defenders.

Storming Your Castle

If starvation, negotiation, and threats were unsuccessful, then the only remaining option was to attack the castle. Enter the siege weapons. In time, catapult bombardment could reduce even a thick wall to rubble. Day after day, night after night, the great swinging arms of the siege machinery outside the walls would pound the stone walls of the castle. And often, from inside the walls, great stone balls would answer back from the defender's own catapults, aimed directly at the attacker's stone throwers.

Eventually, the walls would start to break apart under the onslaught of rock missiles. First a crack, then fracture, then a hole. Once openings appeared that were large enough to move a soldier through, the main frontal assault could begin. On the commander's order, the troops would rush towards the castle, shouting a war cry. An attack on a castle or fortress involved a short, but furious battle, with soldiers attacking holes in the walls with picks and hammers and rushing through as soon as the openings were large enough to squeeze through.

Sometimes, instead of catapults or trebuchets, the attacking army would use miners. These were men who worked underground, spending weeks or months digging tunnels with shovels underneath the walls of the castle. As they dug, they would prop up the walls of the tunnels with timbers to prevent the walls from collapsing. When it was time to attack, soldiers could then go underneath the walls and surprise the besieged by popping up in the middle of the castle grounds.

Another tactical ploy was for the miners to dig away the earth directly under the heavy castle wall. When enough dirt was removed, the weight of the rock walls would collapse it into the hole, allowing the besiegers to rush into the breach.

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If the walls held up to bombardment and mining, then the only option was escalade—climbing the walls. For foot soldiers, escalade just plain sucked. This was perhaps the deadliest, most intense form of ancient warfare. With their shields held overhead, soldiers would climb ladders held against the walls or rush through breaches, their arms furiously swinging two-handed broadswords and battle-axes or charging forward with long sharp pikes in front of them. Hot sand, boiling water, and rocks rained down upon the attackers, adding to the chaos and confusion. On the ramparts, defending archers would cut loose a cloud of iron-tipped arrows, raining them down upon the broken heads and bodies of the luckless attackers below them.

Now, if the attackers had enough time and money, they could build large moveable stairways called siege towers. For the infantry, these were a big improvement from the suicidal scaling ladders. The idea was that the wheeled towers could be moved up against a castle wall and then soldiers could stay protected by the tower walls until it made contact with the ramparts, at which point soldiers could simply run out onto the parapets.

Siege towers were quite popular during the time of the Crusades. Consider for example the Siege of Acre during the Third Crusade. Despite the harassment from Saladin's troops, the Christian Franks continued the siege in earnest. English King Richard the Lionhearted and his French counterpart set their soldiers to work building three huge, movable siege towers with which to attack Acre's walls. These towers were said to be 60 cubits (90 feet) tall and covered with skins which were treated in vinegar, mud, and fire-resistant substances. (It didn't help, they burned down anyway.)

The golden era of siege warfare was over by about the year 1500 AD, but elements of it lasted much longer. With the rise of gunpowder weapons and military aircraft, the defensive advantages provided by the thick walls of a castle waned, and with them so did the popularity siege warfare. That is, until the next fantasy television series comes along.

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